Copyleft licences work by conditioning distribution of a work's binary on providing access to relevant source code. Under the European Computer Programs directive, once a copy of a computer program has been placed in circulation in the EEA by or with the consent of the copyright holder, the copyright holder can no longer control circulation ("exhaustion of rights"). Is the condition to provide source an attempt to control circulation, and is the exhaustion principle problematic for the GPL and other copyleft licences? Commentators have suggested that this is fatal to copyleft, but we argue these analyses are overblown.